This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. POISe is a technique for imaging and/or determining the optical properties of a turbid sample by measuring its surface displacement following irradiation with a short (<10 ns) laser pulse. The technique is enabled by a modified Mach-Zehnder interferometer capable of measuring surface displacements with an axial precision of 0.5 nm, and a temporal resolution of 4 ns. The absorption and reduced scattering coefficients are determined by fitting the POISe measurement to model functions that describe the time-resolved surface deformation as a function of optical and thermophysical properties of the target. We present the capabilities of the instrument and a few preliminary results of the POISe system used to determine the optical properties of two homogeneous, turbid tissue phantoms. We show that the absorption and reduced scattering coefficients estimated by POISe are in relatively good agreement with those derived through the more established method of frequency domain photon migration (FDPM).